1. Field of the Invention
This invention relates generally to windshield wiper systems and, more particularly, to a new and improved pivot shaft transmission and method of mounting the same on a body panel.
2. Description of the Prior Art
In typical automotive windshield wiper systems, individual wiper arms are attached to corresponding pivot shafts rotatably supported on transmissions mounted on a body panel below the windshield. Motive force is supplied by a drive link to one pivot shaft and movement of the wiper arms is synchronized by a cross link between the pivot shafts. Typically, the transmissions are aligned with appropriate apertures in the body panel and fastened thereto with a plurality of fasteners in a manual assembly operation similar to assembly operations encountered in the electronic instrument field where various components having rotatable control shafts are attached to a chassis. In one proposal to simplify the assembly procedure in the electronic instrument environment, an appropriately key-shaped component has a lip which engages an edge of a correspondingly key-shaped panel aperture to provide a fulcrum for pivoting the component to an assembled position in the aperture, the key shapes preventing rotation of the component in the aperture. As the component pivots to the assembled position the lip bends the edge of the panel causing the edges of the aperture to contract and tightly grip the component. This arrangement, while satisfactory in its environment, lacks applicability to windshield wiper systems because forces of considerably higher magnitude and panels of much heavier gage material are encountered in the latter environment. Other attachment proposals involving antenna mounts on vehicle body panels and anchor bolts on structural panels employ similar pivotal installation steps and key-shaped apertures. These latter proposals, however, are also inappropriate in a windhshield wiper environment because in the antenna arrangement a large clamping nut is required around the antenna and in the bolt arrangement the bolt is not positively held in position. A windshield wiper transmission according to this invention represents an improvement over these and other similar proposals in that rigid attachment to the panel is automatic and requires only a single threaded fastener.